Divorced Mains and Crosses

Despite suffering a serious bout of tennis elbow from dead poly, M still could not give up the spin. So he wanted gut/poly to see if the comfort would increase.

To isolate variables, we tried different setups on similar matched racket. Among them, there were two gut/poly hybrids that caught my attention.

Strangely, one played dead from the start while the other played perfectly.

The dead one felt too tight, like it was over-tensioned. We could not load the strings. There was no pocketing, no dwell time. The ball just "touched and flew off". 

M felt he did not have enough time to spin nor shape the shot. This was done only in the the low 50s lbs. I figured it may need some time to break-in.

The good one performed perfectly from the first hit. As expected from gut/poly, it was comfortable, powerful, fast, spinny and had great control. However, it did not last long. Maybe 2 sessions?

Since gut was not cheap, M continued playing with both.

After several sessions with others, we met up and played again. When hitting with both setups, the pocketing had grown so deep it felt like a fishing net!

But yet, after it reached it's maximum stretch, we could feel the strings deflecting the ball back out. The dwell time was long and extended. Both were still playable but rebound angle was high.

Then it dawned on us, that it could be because one string of the hybrid had completely lost tension. Most likely the poly. The other string was actually doing most of the work during ball impact!

Probably something like this chart below?

At point "A", both strings start to lose tension right off the stringing machine. Poly's loss is higher than natural gut.

"B", "D" and the other horizontal lines indicate rest periods where the racket was left unused in a room.

The second big tension drop occurs during "C", which was the first session of play after stringing.

Regardless who strings the rackets, both "A" and "C" would always register the biggest tension loss. Subsequent drops would be slow and gradual.

So, it seems that the poly in M's setup could not hold tension. And the tension gap between the gut and poly had grown too huge. So huge, that their actions during ball impact became divorced, with one string doing almost all the work and the other idling.

And how did I know this feeling? 

I once strung up only the mains on an old test racket and hit some balls with it...